LISTSERV Top 20 statistics  April 2009

There are many possible ways to measure the relative "importance" or
"size" of LISTSERV sites: number of lists, number of subscribers, number
of messages delivered, etc. In most cases, the number of messages
delivered is used to rank mailing list managers, because it is the most
accurate measurement of
the amount of activity on the server. But, depending on what you are looking
for, other variables may be more appropriate. There are currently three LISTSERV
"Top 20" lists, ranking the various servers according to:

What do these numbers mean exactly?

The statistics are gathered daily by a monitor at L-Soft which polls all the LISTSERV
sites that participate in the "open" LISTSERV network over the worldwide Internet.
Corporate servers operating in a "closed" environment are not included.

The statistics are organized in monthly reports. The message volume figures are a flat
average of the accumulated traffic for the entire month. Thus, a server that delivers 300,000
messages per month will show a daily average of 10,000 messages. In practice, there is a lot
less traffic during the weekend, and even during business days there can be significant
fluctuations (~30%). The list statistics (number of lists, number of subscribers, largest
lists in the network) are measured as of the last day in the month.

For the current month, the message volume figures are averaged based on the number of days
that have elapsed. In practice, the figures are not very meaningful in the first few days,
especially if the month starts on a weekend. In that case it is best to refer to the
previous month for more accurate figures.

A fourth "Top 20" list is available for the more technically oriented:
Number of messages generated by the server.
This corresponds to the number of mail messages created
by the server while processing postings to its mailing lists. LISTSERV delivers its mail using
an intelligent mail delivery function called DISTRIBUTE, which improves mail delivery times and
reduces bandwidth usage by spreading the delivery chore over scores of participating servers.
Each of these servers processes the recipients for its service area (typically its organization or
campus). In most cases, DISTRIBUTE simply alters the manner in which the mail is delivered,
and the number of messages forwarded to other sites for optimized delivery is roughly equal to
the number of messages received by other sites for the same purpose. In some cases, however,
this is not the case, either because the server elected to serve a much wider service area than
its own organization, or because it is explicitly forwarding all its deliveries to another
machine (for instance, many mainframe-based servers forward their mail to a workstation or PC
for delivery).